This invention relates to a marine power device, and more particularly to a marine power device for driving various kinds of electric units mounted on a ship in which an outboard motor is used as a propelling equipment by means of a power supply including a battery and a magneto driven by an engine.
In a ship in which an outboard motor is used as a propelling equipment, a power device including a power supply consisting of a magneto driven by an engine and a battery is used for driving various loads. The loads driven by the power device include constantly-driven loads such as an ignition unit for an internal combustion engine, a fuel injection control unit adapted to control a fuel injector for feeding the internal combustion engine with fuel, a pump motor adapted to drive a fuel pump for feeding the injector with fuel and the like, as well as occasionally-driven loads driven as required.
An outboard boat which is a motor boat equipped with an outboard motor often encounters problems such as a decrease in navigation speed thereof due to an action of an underwater portion of the boat as a resistance during high-speed navigation thereof, planing of a bow of the boat during the high-speed navigation and the like. In order to avoid such problems, an inclination mechanism called a trim mechanism is provided, which is constructed so as to incline the propelling equipment by means of a hydraulic cylinder. For arrangement of such an inclination mechanism, it is required that a motor which is called a trim motor and functions to actuate a hydraulic pump for feeding the hydraulic cylinder with hydraulic fluid is driven in the form of an occasionally-driven load.
Also, the outboard boat is often mounted thereon with a hydraulic lift for lifting the whole outboard motor during navigation of the boat in a shoal or the like. In this instance, it is also required that the motor which functions to actuate the pump for applying a hydraulic pressure to the hydraulic cylinder is driven as another occasionally-driven load.
Further, in an outboard boat which is mounted thereon with a plurality of outboard motors, a power assisting unit is often arranged for assisting operation of a steering wheel by means of a hydraulic pressure, to thereby reduce force required for operating the steering wheel. In such a case, it is required that a motor which acts to actuate a pump for applying a hydraulic pressure to the power assisting unit is driven as a further occasionally-driven load.
Other occasionally-driven loads associated with the outboard boat include a start motor for starting the engine, a motor for actuating a bilge pump for discharging bilge-water collected in the boat, a motor for actuating a winding machine for winding up an anchor or a net, a lamp and the like.
A conventional marine power device includes a magneto driven by the internal combustion engine, a DC power circuit which includes a rectification circuit for rectifying an AC output of the magneto and a voltage regulator for restricting an output voltage thereof to a set level or below and is adapted to output a DC voltage limited to a set level or below, and a battery charged by an output of the DC power circuit, wherein such constantly-driven loads and occasionally-driven loads as described above are driven by an output voltage of the battery.
Of the loads driven by the marine power device, the occasionally-driven loads such as the motors which act to drive the pump for applying a hydraulic pressure to the trim mechanism, the lift, the power assisting unit for the steering wheel and the motors for driving the bilge pump and winding machine generally consume a current in a large amount. Thus, when the occasionally-driven loads are connected to the battery while the battery is kept at a state approximating overdischarge, the marine power device fails to normally actuate the constantly-driven loads such as the motors for the pump for feeding the fuel injection control unit and fuel injector with fuel, leading to a reduction in output of the engine and/or interruption of the engine. In particular, a two-cycle engine wherein lubricating oil is fed to the engine while being mixed with fuel often causes seizure thereof because shortage of fed fuel due to a decrease in voltage of the battery leads to shortage of lubricating oil.